In the mid-21st century, dogs are all but extinct. An experiment gone awry caused every canine on Earth to become hyperintelligent. Now the only surviving dogs are relegated to a sanctuary off the coast of Florida: Dog Island. There, they are studied in a wild, feral and protected state. And there, too, their robot replacements are tested before being sold for mass consumption. Seventeen-year-old Nano Miller was born and bred on Dog Island, where life has been mostly wonderful except for annual heartbreak, when another robot dog is torn from her arms and replaced with the latest model.